Welding Deformation Prediction And Control Of Three-Sided Forming Robot For Port Crane

The key structural unit of large lifting equipment is the box beam,whose quality directly affects the velocity of engineering.The large box beam structure is composed of a welding structure such as a splicing plate.If the welding sequence and process parameters are selected reasonably,the post-weld deformation can be significantly reduced and the engineering efficiency can be improved.we use simulation and experiment to predict the welding sequence of box girder structure which under multiple welding robots and different arc quantity conditions,verified the optimal scheme.It is helpful to the follow-up process.while reducing the deformation.Firstly,a plate model is established with length of 500 mm,width of 100 mm and thickness of 1.5mm,to conduct intermittent welding under the conditions of current80 A,voltage 20 V and arc speed of 7.5mm/s.During welding process,We can observed stress field,post-weld deformation and compared with the simulation results under the same conditions.Next,We simulated the welding sequence of plate elements with 2.2m plate length and 3m plate length.The width of the model plate is 2m,and the specification of angle steel is L100x63x8.The welding sequence is designed and simulated under different arc numbers and choose the best scheme.Experiment with the best scheme to verify the simulation results.Then,We simulated the welding sequence of the weld near the diaphragm and established the unit of the box girder.Two welding machines were used to weld them.Three schemes were designed to explore the welding sequence of horizontal and vertical welds.The best scheme was selected by comparing the simulation results,and verified it accuracy.Finally,We simulated the fillet weld of the bottom plate and the webs on both sides.The total length of fillet weld is 10 m.The fillet weld is divide into several blocks.Two welding machines are used to weld the fillet at the same time.The welding sequence of each section of the fillet weld is simulated.There are six welding schemes.The best scheme was selected by comparing the simulation results,and verified it accuracy.Selection of Process Parameters for Discontinuous Plate Welding can ensure penetration and weld shape well.The simulated maximum deformation is 17.23 mm.The measured maximum deformation is 16.53 mm,which has 0.7mm different fromthe simulation value.The welding parameters of plate unit are current 280 A,voltage28 V and welding speed 300 mm/min;the welding parameters of seam near the diaphragm are current 280 A in transverse welding,voltage 27 V,welding speed 300mm/min,current 180 A in vertical welding,voltage 17 V,welding speed 120 mm/min;the fillet welding parameters of three-sided Forming of Box Girder are current 300 A,voltage 29 V,welding speed 400 mm/min can ensure requirements.The experimental results show that the weld has a great appearance and the deformation rules are in accordance with their simulation results.